motor control ideas

[Guest Hickman]

I need to control 12, 3-ph motor-starters, allowing NONE of them to 'start' simultaneously. It's a load-balancing problem, but I only need to balance the start-up period. Any or all 12 units may 'run' simultaneously. I need to limit them to 1 unit starting at a time. I currently have a program written in Concept that 'gets the job done', but it's not very effecient. It checks to see if Input_1 is requesting service. One way or another, it waits 30 seconds before scanning to Input_2, etc. I need a design that scans Input_1 thru Input_12. Once it finds an input that is requesting service, it allows that unit to start, then waits 30 seconds before proceeding with the scan. I hope that makes sense. It's a lot easier for me to understand what I need than it is to try to convey it to others. Thanks in advance for the help!

[Guest Kempfj]

Give us the plc info and the I/O configuration. Can the motors be started in 1 thru 12 sequence? What about shutdown, interlocks and manual operation? I'd use proworkx NxT to do it. I think it'll convert it to concept.

[Guest Hickman]

I'm using a Momentum: 24 VDC power, inputs and outputs. There are 16 ins and 16 outs. [Can the motors be started in 1 thru 12 sequence?] They should be 'checked' for service in order. These units are currently started by pressure or temperature or humidity or .... whatever. That will remain the case. I will place relays in-line to allow control by the PLC. Again, I'm only controlling the start-up of each unit. [What about shutdown, interlocks and manual operation?] This part of the design is irrelevant. My only requirements are as stated in the original question. [i'd use proworkx NxT to do it. I think it'll convert it to concept.] I don't have ProWorkx Nxt. I have Concept. The logic is the same no matter what you write it in. Edited 18 Aug 2003 by Hickman